/*
 * Copyright (c) 2004-2022, University of Oslo
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 * Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 * Neither the name of the HISP project nor the names of its contributors may
 * be used to endorse or promote products derived from this software without
 * specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
package org.hisp.dhis.period;

import com.google.common.collect.Lists;
import java.time.DayOfWeek;
import java.time.LocalDate;
import java.time.temporal.WeekFields;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import org.hisp.dhis.calendar.Calendar;
import org.hisp.dhis.calendar.DateTimeUnit;

/**
 * @author Kristian Wærstad
 */
public abstract class BiWeeklyAbstractPeriodType extends CalendarPeriodType {
  protected final String name;

  protected final int startOfWeek;

  protected final String isoFormat;

  protected final String isoDuration;

  protected final int frequencyOrder;

  protected final String sqlInterval;

  protected final String weekPrefix;

  protected BiWeeklyAbstractPeriodType(
      String name,
      int startOfWeek,
      String isoFormat,
      String isoDuration,
      int frequencyOrder,
      String sqlInterval,
      String weekPrefix) {
    this.name = name;
    this.startOfWeek = startOfWeek;
    this.isoFormat = isoFormat;
    this.isoDuration = isoDuration;
    this.frequencyOrder = frequencyOrder;
    this.sqlInterval = sqlInterval;
    this.weekPrefix = weekPrefix;
  }

  public int getStartOfWeek() {
    return startOfWeek;
  }

  @Override
  public String getIso8601Duration() {
    return isoDuration;
  }

  @Override
  public int getFrequencyOrder() {
    return frequencyOrder;
  }

  @Override
  public String getSqlInterval() {
    return sqlInterval;
  }

  @Override
  public String getIsoFormat() {
    return isoFormat;
  }

  @Override
  public Period createPeriod(DateTimeUnit dateTimeUnit, Calendar calendar) {
    DateTimeUnit start = adjustToStartOfBiWeek(new DateTimeUnit(dateTimeUnit), calendar);
    DateTimeUnit end = new DateTimeUnit(start);
    end = calendar.plusDays(end, calendar.daysInWeek() * 2 - 1);

    return toIsoPeriod(start, end, calendar);
  }

  @Override
  protected DateTimeUnit getDateWithOffset(
      DateTimeUnit dateTimeUnit, int offset, Calendar calendar) {
    return calendar.plusWeeks(dateTimeUnit, 2 * offset);
  }

  /**
   * Generates bi-weekly Periods for the whole year in which the given Period's startDate exists.
   */
  @Override
  public List<Period> generatePeriods(DateTimeUnit start) {
    Calendar calendar = getCalendar();
    List<Period> periods = new ArrayList<>();
    DateTimeUnit date = adjustToStartOfBiWeek(start, calendar);
    date = adjustToStartOfBiWeek(calendar.fromIso(date.getYear(), 1, 1), calendar);

    for (int i = 0; i < calendar.weeksInYear(start.getYear()) / 2; i++) {
      periods.add(createPeriod(date, calendar));
      date = calendar.plusWeeks(date, 2);
    }

    return periods;
  }

  /**
   * Generates the last 26 bi-weeks where the last one is the week which the given date is inside.
   */
  @Override
  public List<Period> generateRollingPeriods(DateTimeUnit end, Calendar calendar) {
    List<Period> periods = Lists.newArrayList();
    DateTimeUnit date = adjustToStartOfBiWeek(end, calendar);
    date = calendar.minusDays(date, 350);

    for (int i = 0; i < 26; i++) {
      periods.add(createPeriod(date, calendar));
      date = calendar.plusWeeks(date, 2);
    }

    return periods;
  }

  @Override
  public String getIsoDate(DateTimeUnit dateTimeUnit, Calendar calendar) {
    int year;
    int week;

    if (calendar.isIso8601()) {
      LocalDate date =
          LocalDate.of(dateTimeUnit.getYear(), dateTimeUnit.getMonth(), dateTimeUnit.getDay());
      WeekFields weekFields = WeekFields.of(DayOfWeek.MONDAY, 4);

      year = date.get(weekFields.weekBasedYear());
      week = (date.get(weekFields.weekOfWeekBasedYear()) / 2) + 1;
    } else {
      DateTimeUnit date = adjustToStartOfBiWeek(dateTimeUnit, calendar);
      week = calendar.week(date);

      if (week == 1 && date.getMonth() == calendar.monthsInYear()) {
        date.setYear(date.getYear() + 1);
      }

      year = date.getYear();
    }

    return String.format("%d%s%d", year, weekPrefix, week);
  }

  @Override
  public Date getRewindedDate(Date date, Integer rewindedPeriods) {
    Calendar cal = getCalendar();

    Date rewindedDate = date != null ? date : new Date();
    rewindedPeriods = rewindedPeriods != null ? rewindedPeriods : 1;

    DateTimeUnit dateTimeUnit = createLocalDateUnitInstance(rewindedDate);
    dateTimeUnit = cal.minusWeeks(dateTimeUnit, rewindedPeriods * 2);

    return cal.toIso(dateTimeUnit).toJdkDate();
  }

  public DateTimeUnit adjustToStartOfBiWeek(DateTimeUnit dateTimeUnit, Calendar calendar) {
    int biWeekday = calendar.weekday(dateTimeUnit) + (1 - (calendar.week(dateTimeUnit) % 2)) * 7;

    if (biWeekday > startOfWeek) {
      dateTimeUnit = calendar.minusDays(dateTimeUnit, biWeekday - startOfWeek);
    } else if (biWeekday < startOfWeek) {
      dateTimeUnit = calendar.minusDays(dateTimeUnit, biWeekday + (frequencyOrder - startOfWeek));
    }

    return dateTimeUnit;
  }
}
